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Chestnut and Leek Soup with Cider, Thyme and Crisp Crumbs
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Sweet chestnut burrs split open and thud down through October, spiny green husks cracking on the path under old Castanea trees in parks, hedgerows and smallholdings across Europe and East Asia. Gathered the same morning they fall, the nuts are starchy rather than oily — which is exactly why they build a soup with the body of cream and none of the weight. Dry cider and a late cut of thyme keep all that sweetness in line.
1 lb 2 oz (500 g) fresh sweet chestnuts in shell, or 14 oz (400 g) vacuum-packed cooked chestnuts
3 medium leeks, about 1 lb 2 oz (500 g) trimmed weight, white and pale green parts, sliced into thin rings
3 tbsp (45 g) unsalted butter
1 tbsp (15 ml) olive oil, plus more to finish
1 tart apple, about 5 oz (150 g), peeled and diced — Bramley, Granny Smith or Shinano Gold
2 fresh bay leaves and 4 sprigs thyme, tied together with string
⅔ cup (150 ml) dry cider, or apple juice plus 1 tsp cider vinegar
5 cups (1.2 litres) light chicken or vegetable stock
⅓ cup (80 ml) double cream or crème fraîche
1 tsp cider vinegar, plus a fresh grating of nutmeg
2 tbsp chopped chives, and flaky salt and coarse black pepper to finish
The Recipe
Heat the oven to 400 °F (200 °C). Cut a bold cross through the shell on the domed side of each chestnut, going through the leathery brown shell and the thin inner skin but not deep into the nut — the slit lets steam escape and pries the shell open for you. Roast on a tray for 20–25 minutes, until the cut edges curl back and the kitchen smells sweet and toasted.
Tip the hot chestnuts into a folded tea towel, wrap them up and peel them while they are almost too hot to handle, five or six at a time. Do not skip this: the papery pellicle under the shell grips tight as the nut cools, and cold chestnuts give up their skins in frustrating shreds. (With vacuum-packed chestnuts, skip steps 1 and 2 entirely.)
Set aside 3½ oz (100 g) of the peeled nuts. Melt 1 tbsp (15 g) of the butter in a frying pan over medium heat, add these reserved chestnuts and fry for 4–5 minutes, tossing, until their edges are deep brown and they crackle when you press one with a spoon. Lift out onto kitchen paper with a pinch of salt — these are the crisp crumbs for the top, and the browning gives the finished bowl the roasted note that a smooth purée always loses.
In a heavy pot, melt the remaining 2 tbsp (30 g) butter with the olive oil. Add the leeks, the bay and thyme bundle and ½ tsp salt, cover, and sweat over medium-low heat for 12–15 minutes, stirring now and then. They should collapse to translucent ribbons with no colour at all: scorched leek turns grey-green and bitter, and that bitterness never leaves the soup once it is blended.
Stir in the diced apple and cook uncovered for 3 minutes, then pour in the cider. Let it bubble for 3–4 minutes until the sharp alcoholic smell at the surface rounds out into something closer to baked apple — pour the stock in too early and that raw edge stays locked in the soup.
Add the remaining chestnuts and the stock. Bring to a gentle simmer, partly cover, and cook for 20 minutes, until a chestnut crushes against the side of the pot under light pressure from a spoon, with no chalky core. Fish out the bay and thyme bundle and discard it.
Ladle out and reserve about 1 cup (240 ml) of the cooking liquid, then blend the rest in short bursts of 10 seconds until velvety, adding reserved liquid until it coats a spoon and slides off slowly. Blend in brief pulses only — chestnut starch turns gummy and pasty under a long high-speed thrash, exactly like overworked mashed potato.
Return the soup to low heat, stir in the cream and warm it without letting it bubble, then season with the cider vinegar, nutmeg, salt and pepper. Taste before and after the vinegar: chestnut sweetness reads as flat and slightly cloying until acid sharpens it, and that single teaspoon is what makes the soup taste of autumn woodland rather than dessert.
Serve in warmed bowls, scattered with the fried chestnut crumbs and chives, a thread of olive oil and coarse pepper. Add the crumbs at the table, not in the kitchen — they soften within two minutes in hot soup.
